Shear-free Null Quasi-Spherical Spacetimes
نویسنده
چکیده
We study the residual gauge freedom within the null quasi-spherical (NQS) gauge for spacetimes admitting an expanding shear-free null foliation. By constructing the most general NQS coordinates subordinate to such a foliation, we obtain both a clear picture of the geometric nature of the residual coordinate freedom, and an explicit construction of nontrivial NQS metrics representing some well-known spacetimes, such as Schwarzschild, accelerated Minkowski, and Robinson-Trautman. These examples will be useful in testing numerical evolution codes. The geometric gauge freedom consists of an arbitrary boost and rotation at each coordinate sphere — and this freedom may be used to normalise the coordinate to an “inertial” frame. 04.20,04.30 Typeset using REVTEX ∗from March 1997: [email protected]
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